package com.hmdp.service.impl;

import com.hmdp.dto.Result;
import com.hmdp.entity.SeckillVoucher;
import com.hmdp.entity.VoucherOrder;
import com.hmdp.mapper.VoucherOrderMapper;
import com.hmdp.service.ISeckillVoucherService;
import com.hmdp.service.IVoucherOrderService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.utils.RedisIdWorker;
import com.hmdp.utils.UserHolder;
import org.redisson.api.RLock;
import org.redisson.api.RedissonClient;
import org.springframework.aop.framework.AopContext;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.core.io.ClassPathResource;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.data.redis.core.script.DefaultRedisScript;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import javax.annotation.PostConstruct;
import javax.annotation.Resource;
import java.time.LocalDateTime;
import java.util.Collections;
import java.util.concurrent.ArrayBlockingQueue;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;

/**
 * <p>
 *  服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class VoucherOrderServiceImpl extends ServiceImpl<VoucherOrderMapper, VoucherOrder> implements IVoucherOrderService {

    @Autowired
    private ISeckillVoucherService iSeckillVoucherService;

    @Autowired
    private RedisIdWorker redisIdWorker;

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Autowired
    private RedissonClient redissonClient;

    private IVoucherOrderService proxy;//定义代理对象，提前定义后面会用到
    //注入脚本
    private static final DefaultRedisScript<Long> SECKILL_SCRIPT;
    static {
        SECKILL_SCRIPT = new DefaultRedisScript<>();
        SECKILL_SCRIPT.setLocation(new ClassPathResource("seckill.lua"));
        SECKILL_SCRIPT.setResultType(Long.class);
    }

    //异步处理线程池
    private static final ExecutorService SECKILL_ORDER_EXECUTOR = Executors.newSingleThreadExecutor();

    //在类初始化之后执行，因为当这个类初始化好了之后，随时都是有可能要执行的
    @PostConstruct
    private void init() {
        SECKILL_ORDER_EXECUTOR.submit(new VoucherOrderHandler());
    }
    // 用于线程池处理的任务
// 当初始化完毕后，就会去从对列中去拿信息
    private class VoucherOrderHandler implements Runnable {

        @Override
        public void run() {
            while (true) {
                try {
                    // 1.获取队列中的订单信息
                    VoucherOrder voucherOrder = orderTasks.take();
                    // 2.创建订单
                    handleVoucherOrder(voucherOrder);
                } catch (Exception e) {
                    log.error("处理订单异常", e);
                }
            }
        }

        private void handleVoucherOrder(VoucherOrder voucherOrder) {
            //1.获取用户
            Long userId = voucherOrder.getUserId();
            // 2.创建锁对象
            RLock redisLock = redissonClient.getLock("lock:order:" + userId);
            // 3.尝试获取锁
            boolean isLock = redisLock.tryLock();
            // 4.判断是否获得锁成功
            if (!isLock) {
                // 获取锁失败，直接返回失败或者重试
                log.error("不允许重复下单！");
                return;
            }
            try {
                //注意：由于是spring的事务是放在threadLocal中，此时的是多线程，事务会失效
                proxy.createVoucherOrder(voucherOrder);
            } finally {
                // 释放锁
                redisLock.unlock();
            }
        }
    }

        //a
        private BlockingQueue<VoucherOrder> orderTasks = new ArrayBlockingQueue<>(1024 * 1024);

        @Override
        public Result seckillVoucher(Long voucherId) {
//        //1.查询优惠劵
//        SeckillVoucher voucher = iSeckillVoucherService.getById(voucherId);
//        //2.判断秒杀是否开始
//        LocalDateTime beginTime = voucher.getBeginTime();
//        if (beginTime.isAfter(LocalDateTime.now())) {
//            //尚未开始
//            return Result.fail("活动尚未开始");
//        }
//        //3.判断秒杀是否已经结束
//        LocalDateTime endTime = voucher.getEndTime();
//        if (LocalDateTime.now().isAfter(endTime)) {
//            //已结束
//            return Result.fail("活动已经结束");
//        }
//        //4判断库存是否充足
//        if (voucher.getStock() < 1) {
//            //库存不足
//            return Result.fail("库存不足!");
//        }
            Long userId = UserHolder.getUser().getId();
            long orderId = redisIdWorker.nextId("order");
            // 1.执行lua脚本
            Long result = stringRedisTemplate.execute(
                    SECKILL_SCRIPT,
                    Collections.emptyList(),
                    voucherId.toString(), userId.toString(), String.valueOf(orderId)
            );
            int r = result.intValue();
            // 2.判断结果是否为0
            if (r != 0) {
                // 2.1.不为0 ，代表没有购买资格
                return Result.fail(r == 1 ? "库存不足" : "不能重复下单");
            }
            //TODO 保存阻塞队列
            VoucherOrder voucherOrder = new VoucherOrder();
            //订单id
            voucherOrder.setId(orderId);
            //用户id
            voucherOrder.setUserId(userId);
            //优惠券id
            voucherOrder.setVoucherId(voucherId);
            orderTasks.add(voucherOrder);

            //获取代理对象
            proxy = (IVoucherOrderService) AopContext.currentProxy();
            // 3.返回订单id
            return Result.ok(orderId);

        }
            //不用这个锁了setnx存在这不可重入 释放锁 主从一致 并且不可重试
            // SimpleRedisLock lock = new SimpleRedisLock(stringRedisTemplate, "order:" + userId);
            //获取锁对象
            // boolean isLock = lock.tryLock(1200);
//        RLock rLock = redissonClient.getLock("lock:order:" + userId);
//        boolean isLock =rLock.tryLock();
//        //加锁失败
//        if (!isLock) {
//            return Result.fail("不允许重复下单");
//        }
//        try {
//            //获取代理对象(事务)
//            IVoucherOrderService proxy = (IVoucherOrderService) AopContext.currentProxy();
//            return proxy.createVoucherOrder(voucherId);
//        } finally {
//            //释放锁
//            rLock.unlock();
//        }




//    @Transactional
//    public  Result createVoucherOrder(Long voucherId) {
//        //6.一个人一单
//        Long userId = UserHolder.getUser().getId();
//        //6.1查询订单
//        int count = query().eq("user_id", userId).eq("voucher_id", voucherId).count();
//        //6.2判断是否存在
//        if (count > 0) {
//            //用户以及购买过
//            return Result.fail("用户已经购买过一次");
//        }
//        //7.扣减库存
//        boolean success = iSeckillVoucherService.update()
//                .setSql("stock =stock -1")
//                .eq("voucher_id", voucherId)
//                .gt("stock", 0).update();
//        if (!success) {
//            //扣减失败
//            return Result.fail("库存不足!");
//        }
//        //8.创建订单
//        VoucherOrder voucherOrder = new VoucherOrder();
//        //8.1 订单id
//        long orderId = redisIdWorker.nextId("order");
//        voucherOrder.setId(orderId);
//        //8.2 用户id
//        voucherOrder.setUserId(userId);
//        //8.3 代金券id
//        voucherOrder.setVoucherId(v oucherId);
//        save(voucherOrder);
//        // 9.返回订单id
//        return Result.ok(orderId);
//    }


        @Transactional
        public void createVoucherOrder(VoucherOrder voucherOrder) {
            Long userId = voucherOrder.getUserId();
            // 5.1.查询订单
            int count = query().eq("user_id", userId).eq("voucher_id", voucherOrder.getVoucherId()).count();
            // 5.2.判断是否存在
            if (count > 0) {
                // 用户已经购买过了
                log.error("用户已经购买过了");
                return;
            }

            // 6.扣减库存
            boolean success = iSeckillVoucherService.update()
                    .setSql("stock = stock - 1") // set stock = stock - 1
                    .eq("voucher_id", voucherOrder.getVoucherId()).gt("stock", 0) // where id = ? and stock > 0
                    .update();
            if (!success) {
                // 扣减失败
                log.error("库存不足");
                return;
            }
            save(voucherOrder);

        }


}
